Urgent Call: All Power To The ISS!

Update Feb 5th 2019, 16:36 UTC: Feedback is overwhelming, will try to update this page as good as possible! Note that we will only receive signal strength value for 435-438 MHz, we will not be able to decode the data.

Update Feb 6th 2019, 08:49 UTC: Thanks for all the transmissions! For today, please look at the “reserved” spots below and try to find another frequency if you are in the same location/ area, as these guys might use the frequencies again. We might not be able to update the list below today, so please use the comment section to indicate planned use instead of sending emails. Good luck & have fun!

Update Feb 7th 2019, 19:17 UTC: Amazing work everyone! Experiment ends today at midnight (UTC), since the device is only recording until then. From tomorrow morning 9/10 UTC we record again, but we do not know yet if and when we can download the data.


We were just informed that it is likely that MarconISSta will be deinstalled on February 9th 2019. This is about three weeks earlier than expected, so we quickly have to finish any outstanding activities. Therefore: All Power To The ISS!

We want to invite everybody who owns a UHF antenna, preferably with an e.i.r.p. of more than 30 dBW (we did successful tests with 50W transmit power and 15 dBi antenna gain), to do transmissions to the ISS. These transmissions will be recorded by MarconISSta and we will publish the results here. This experiment is a nice way for you to test your antennas, while it is great for us and ARISS to evaluate the ARISS VHF/UHF antenna pattern.

Transmission Details:

  • Trasmission time: Whenever you see the ISS between now and February 9th. Next time that we will downlink data is on February 8th, so if you want to make sure that you get the results early, transmit before February 8th.
  • Frequency: 435-438 MHz. Please avoid 435.95 MHz in Europe (our reference frequency) and 436.5 MHz (center frequency of receiver)
  • Power: Continuous transmission of carrier, we recommend  an e.i.r.p. of more than 30 dBW. The reason for this is that MarconISSta integrates the transmissions, short bursts might get lost.
  • Please do not use Doppler correction. We want to see the Doppler shift, it might help us to localize your transmission from this

Results will be published over the weekend.

Please let us know about your transmissions in the comments!

EDIT: To prevent overlap, we will post intended transmissions below:

435.050 MHz: KM39gc (Greece), SV8QG
435.163 MHZ: G3VZV, IO92QA
435.250 MHz: FF46ro, CE3RY
435.300 MHz: Europe
435.325 MHz: FF46QI, CE3QC
435.350 MHz: 05 Feb 19, 19:24 UTC, IV3RYQ
435.350 MHz: EB1ASA
435.375 MHz: 06 Feb 19, several passes over Europe, IN87KM
435.435 MHz: 06 Feb 19, 12.03 and at 19.30 utc (JN65qt), IV3RYQ
435.440  MHz: 05 Feb 19, 17:45 -17:55 UTC, HB9WDF
435.500 MHz: Europe, MX0MXO
435.550 MHz: Europe, ON7UX, ON4ISS
435.580 MHz: 05 Feb 19, 19:21 UTC, SQ6PNV
435.950 MHz: Europe
435.600 MHz: Italy
436.100 MHz: DM91SK, AA5PK
436.500 MHz: Do not use Worldwide – Center frequency (DC Offset)
436.625/.635 MHz: 05 Feb 19, 14:33-14:42 UTC, 16:09 UTC, OH2FQV
436.700 MHz: JO82II, SQ3DHO
436.800 MHz: 06 Feb 19, 01:44-01:52 UTC, PV8DX
437.000 MHz: 05 Feb 19, 19:06-19:09
437.280 MHz: 06 Feb 19, 01:33-01:44 UTC, K4KDR
437.333 MHz: 05 Feb 19 19:20 UTC, JO54DI
437.485 MHz: Italy
437.700 MHz: 06 Feb 19 01:40 UTC, 08:29 UTC, EM90eg, KB4PML

FYI: Yesterday (Feb 5th 2019) we had more visits (2468) on this blog than on any other day! Thanks for all the good work!


126 thoughts on “Urgent Call: All Power To The ISS!

  1. IZ5ILX
    ORBIT # 115530
    AOS : 18:22 z LOS: 18:34 z
    MAX ELEV : 25°
    QRG : 1268.300 23Cm
    2 X 23 YAGI – H POL – 20W
    GRID – JN54AC –

    73s VALE


    1. It is not as bad as it seems. There are two sources for the high power in central Europe: APRS and Radar systems. APRS signals originate both from ground and the ARISS transceivers. Have in mind that we are only connected to a coupled port of the ARISS system, which means that we are “interfered” by their transmissions as well. The radar systems are high-power, but short pulses. The long integration times of MarconISSta make it difficult to identify signals, but we will try our best. You can help by putting your comment below the figures in which you can see your signals. In parallel, we will play with the colormaps on our side and try to find as many of your transmissions as possible. Stay tuned!


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